Tallgrass Communities Mapping Project

Tallgrass ecosystems are one of the world’s most endangered vegetation communities. In southern Ontario, these grasslands once covered 1172 km2. Today tallgrass prairies and savannas are rare in Ontario due to land conversion and fire suppression. It is estimated currently that less than 3% of the original extent of Tallgrass ecosystems within Ontario still exists in fair to good condition. An additional 3% of poor quality remnant Tallgrass communities also remain, but these require intensive restoration and management in order to return them to a healthy, diverse state. Within southern Ontario, Tallgrass ecosystems are most commonly found on sandy plains and moraines (oak savannas) and on clay plains associated with the lower Great Lakes (lake plain prairies).

The Tallgrass Communities Mapping Project has its roots in an earlier TgO project called Save Ontario Savannas initiated in 2001 to fulfill key objectives of the Tallgrass Communities of Southern Ontario Recovery Plan:

  • To encourage Tallgrass habitat conservation and maintenance by identifying and supporting landowners of Tallgrass and savanna remnants to commit to and take action to protect, enhance and expand their sites. A remnant/community approach is designed to benefit multiple species at risk and prevent other associated species from becoming at risk.
  • To enable landowners and their neighbours and community to become actively involved in stewardship of Tallgrass and savanna sites in their geographic area.
  • To develop a comprehensive database of Tallgrass and savanna sites, providing benchmarks against which the remnant can be evaluated and tracked over time. Such information will allow provision of support and intervention to help maintain and expand sites.


The first phase (SOS I) consisted of amassing data on landowners and site information, including maps and legal property descriptions. The sites were then ranked and analyzed based on threat to the Tallgrass community.

SOS II initiated landowner contact. An introductory letter and information about tallgrass prairie and savanna were sent to the complete list of landowners. Media releases were sent to news organizations in target counties. Landowners and local conservation authorities and stewardship committees were contacted. Telephone calls were then made to landowners of the highest ranked prairies and savannas. Visits were made to sites by invitation of the landowner, where the site was evaluated, management techniques recommended and stewardship support requested.

  • SOS II recommendations for the next phase of the project included:
  • Development of management template for landowners
  • Development of management guide geared for rural landowners of remnants and recreations
  • Improved mapping and property information for adjacent landowners
  • Ongoing contact via newsletters, Open House activities, and special mailings
  • Species specific fact sheets to help with identification and management


SOS III was initiated in January, 2003 to carry out the next phase based on the recommendations. A prototype GIS was constructed and approved by March 2003, and a landowner visit program initiated based on previous methodologies. A geographic information system (GIS) is a conceptualized framework that provides the ability to capture and analyze spatial and geographic data. Several open houses were conducted, and a landowner’s manual commissioned. By 2004 over 100 visits have been made to sites, and an ACCESS database created, which includes information on remnant sites as well as adjacent property owner sites.

SOS IV was the wrap-up phase of this project which included fine-tuning of the GIS and completion of data input to the ACCESS database through 2007. The geographical focus next will be the remaining parts of Essex, Lambton and Elgin counties, Huron and Prince Edward Counties, as well as sites in Northwestern Ontario – a new area of interest for TgO.

In 2007, TgO and the Nature Conservancy of Canada (NCC) teamed up for a project to assemble and develop a comprehensive spatial layer of Tallgrass ecosystem mapping for recovery efforts in Ontario. Data was assembled for the analysis from a variety of sources. The present extent of Tallgrass remnants within the current GIS database originated from data provided by Ontario Parks, Ontario Ministry of Natural Resources, TgO’s field work from 2001-2007 and the NCC. In 2010 this project was further enhanced through a partnership between TgO and the Natural Heritage Information Centre (NHIC), a branch of the Ministry of Natural Resources. In 2011, while this work was ongoing, a partnership between TgO and Sir Sanford Flemming College further added to the GIS mapping database.

The main purpose of this cooperative effort was to analyze and compare site information to determine a site’s capability of supporting Tallgrass Prairie vegetation communities and to determine which sites had the highest potential for successful restoration to Tallgrass Prairie. A multiple variable matrix was used to determine site suitability, including site factors such as connectivity, soils, drainage, presence of indicator species, and aspect. In total 43 sites, a subset of the potential sites provided by TgO, were included in the analysis.
TgO received a grant in 2013 from the Habitat Stewardship Fund (HSP) of Environment Canada, to update our GIS mapping of Tallgrass communities in southern Ontario.

This latter phase of the project supported additional research, data acquisition, analysis, air photo interpretation, and reference review of existing prairie remnants for ownership, past land management practices, connectivity and proximity to other prairie habitats, soils, and exposure.

Further analysis of the GIS dataset has produced a comprehensive GIS mapping database of Tallgrass ecosystem remnants for southern Ontario. The analysis incorporated restored and created habitats into the database to complete the Tallgrass Ecosystem Recovery Area. This additional data has assisted in identifying restoration and creation work already completed and will help identify high priority Tallgrass Prairie restoration opportunities for future implementation. The completed dataset will assist in efforts to restore and protect grasslands in the Tallgrass Ecosystem Recovery Areas for southern Ontario.

Recovery of Tallgrass Prairie, Savannah and Woodland remnants was identified as one of the main objectives of the Tallgrass Ecosystem Action Plan and one of the instrumental reasons for the formation of TgO in 2001. This project will be an important tool in guiding and directing further recovery of Tallgrass ecosystems in Ontario, in order to restore and enhance existing remnants to a larger, connected, functioning ecosystem. This targeted approach will lead to increased habitat for many rare and/or Species at Risk which rely upon the endangered Tallgrass ecosystems of Ontario in order to survive.

TgO has completed our outreach to various data partners and compiled the latest dataset of known Tallgrass community remnants and created projects. This dataset is now undergoing a quality assurance and quality control (QA/QC) check involving our partners, in order to ensure that the dataset is as accurate as possible. Maps generated from the GIS dataset are available for download from this website. Dataset distribution to the provincial repository at the Natural Heritage Information Centre (NHIC) will be forthcoming upon completion of the QA/QC exercise.

A link to the maps can be found here.

For further information on the project, please contact: info@tallgrassontario.org

Presentations of TgO’s Save Ontario Savannas project have been made by Will Wilson and his team to the North American Prairie Conference (Madison, August 2005), Natural Areas Conference (Chicago, October, 2005) and Species at Risk Conference (Peterborough, October 2005). Click here to download.